If You Don't Know About This Weird Feature In Dropbox, All Your Files Could Be Deleted

Friday

Apr 11, 2014 at 4:31 PM

Julie Bort

Dr. Paul Riley, a researcher at the University of Nottingham, loves Dropbox. But recently he had a terrifying experience in which hundreds of his files suddenly vanished.

He's a renewable energy expert and an electrical engineer leading a project to build a cooking stove for developing countries that generates electricity by burning wood or dung.

Let's just say he's not a technical Luddite.

But it took him days to unravel this baffling problem with Dropbox, in which about 600 of his files were mysteriously deleted, and then restored, and then deleted again.

And not just from his folder, but from the hard drives of six of his colleague's laptops which had linked to the folder.

He shared his story with Business Insider to warn others.

It all began a few weeks after he had shared a folder with a colleague named "Joe."

"I tried to do some work and I couldn't find any of the data. The whole Dropbox folder that Joe had been given access to had been wiped out," Riley told us.

Dropbox has a feature that allows you to see which person deleted files. It showed that Joe was the culprit, but Joe insisted he didn't delete any of the files.

Just as suddenly, the files reappeared.

It turns out, this situation was due to how Dropbox handles shared folders when using network drives.

Dropbox has a feature called sync. When you sync files, Dropbox automatically updates all copies of the file on everyone's hard drives. If a file is removed from the folder, Dropbox automatically removes it from everyone's hard drives, even the person who owns the folder.

Joe installed Dropbox on his laptop but didn't want all of Riley's files on the laptop's hard drive. So he stored his copies of the files in Dropbox on the university's network server.

And that was the problem.

When he left his office, he unplugged from the university's network, and (obviously), the files on the network server vanished from his laptop. Dropbox noticed that the files were gone, and so it deleted them from everyone else's laptops, too.

The files weren't gone forever. When Joe came back to his office and plugged his laptop back into the network, the file reappeared in his Dropbox folder and were automatically reinstalled on everyone's laptops.

But this deleting/reinstalling was wreaking havoc with the team, particularly with folks in developing countries like Nepal, India, and the Philippines where the Internet is slow. It was sucking up their bandwidth. Worse, it was corrupting some of the files.

After a few days of investigating, Riley discovered that the solution was pretty simple. Joe just had to keep all of Riley's files on his laptop.

"I think Dropbox is a wonderful piece of software, that’s why we use it, but it does have problems," he said.

Riley wasn't in danger of losing his files for good. Dropbox keeps backups on its service for 30 days, too, a feature Riley praises as "very good."

A Dropbox spokesperson says deleting files when a network drive vanishes is neither a problem nor a glitch. It's Dropbox's way of making sure everyone's folders are automatically up to date. The spokesperson says it warns people about using disk drives that can be disconnected, too.

The company sent us this statement:

“We’re sorry to hear about the professor’s challenges. Services like Dropbox rely on access to shared documents in order to keep them in sync across all users. If the system can’t find the file because an external storage source has been disconnected while the application is running, that will be interpreted as the file being deleted. This is why our website warns users against placing the Dropbox folder and its files on external storage. We’re always happy to talk with users who have questions about the service.”

Here's the warning that Dropbox has posted on its website:

"If the external drive is disconnected from the computer while Dropbox is running, there's a small chance that the application will start deleting files before realizing that the entire drive has been removed. Again: When it comes to using an external drive for your Dropbox folder, tread carefully."

Other file sharing services say they protect users from this problem. Egnyte, a file-sharing service for enterprises, says that it won't delete synced files just because a network drive goes missing. "Simply disconnecting from a network drive does not constitute a delete. An explicit delete is expected from the user," says Rajesh Ram, co-founder and VP of product management of Egnyte, a file-sharing service for enterprises.

And a Box spokesperson says it doesn't offer the sync function with network drives at all, even though users have been asking for it.

The upshot is: the sync function in Dropbox is powerful and something many users love. But make sure that everyone in your team knows to keep synced files on their laptops, not remote networks, or your files could vanish, too.

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